Hello.
As you might know, on July 1th, 2012 time was changed to 1 seconds back, which affected some NTP-enabled systems.
Symptoms are server lockup and high cpu usage for some processes.
We've got reports about Debian6 and Ubuntu12 servers running nxagentd.
Fix:
* Upgrade tzdata packages
* Either reboot server or stop ntpd then set date manually and then restart ntp and affected applications
UPDATE: looks like it's enough to just jump time a couple of seconds ahead using "date" command, no need to restart anything. Ntpd then will resolve this jump.
Also please check Marco's blog for more details.
More info:
http://my.opera.com/marcomarongiu/blog/2012/06/01/an-humble-attempt-to-work-around-the-leap-second
https://lkml.org/lkml/2012/7/1/203
For those affected, jumping with the date command can be accomplished with:
date; sudo date `date +"%m%d%H%M%C%y.%S"`; date;
One additional note, if this is a virtualized machine make sure to check the host server it is running on as well for the issue, it was the cause for us.